HobbyKing EPP FPV

I have been dealing with arducopter since some time but I am rather new to arduplane. Yesterday I had my first flight on my HK EPP FPV and could not really engage the autopilot as when switching to stabilize mode the plane started to move the tail from one side to the other like crazy. I have attached a snapshot of the yaw plots and also the log file. Any help on what to tweak on the APM would be greatly appreciated, parameters are pretty much set to their default values.
[attachment=0]2014-03-07 17-45-26.zip[/attachment]

On the ground in Stabilize, does your rudder go right when the right aileron goes up?

Yes, indeed it does and full throws, is that normal?
Thanks for your response

Full throws, no, about a 1/4 throw yes. The EPP FPV can fly happily without rudder so one work around is to disable it or just disconnect the servo.
I suspect that one of the parameters for rudder is too high, perhaps a decimal point in the wrong place so 1.000 instead of 0.100?
If possible post your parameter file here?

Hi Graham,
you were right, actually I had the parameter KFF_RDDRMIX (Aileron to rudder mix) set to 25 thinking it required a figure in %. I have changed it to 0.25 and now there is only a small rudder movement when the roll is moving.
Thanks for pointing me to the right direction, I need know to test it again in flight although I have to solve other problems; I am using a dragon link system but F/S was triggered several times during the flight at very short distances (< 1km), also the plane looked underpowered so I need to change the propeller.

Glad to help, I had a EPP FPV for a while and one major addition I did was to make an steel insert for the spar so that I got 4 degrees of dihedral which made the plane much, MUCH nicer to fly.

Power-wise I think I was getting about 250-300W or so and power was very adequate even at 1600m (5200ft) that I fly at.

Can’t help with the Dragonlink though as I have no experience with it, but check antenna lengths, types, placement and any possible source of interference.